#include <os_internal.h>
#include "controller.h"

#define CHECK_IPAGE(p, pfs)                                                                                   \
	(((p).ipage >= (pfs).inode_start_page) && ((p).inode_t.bank < (pfs).banks) && ((p).inode_t.page >= 0x01) && \
	 ((p).inode_t.page < 0x80))

s32 __osPfsGetNextPage(OSPfs *pfs, u8 *bank, __OSInode *inode, __OSInodeUnit *page)
{
	s32 ret;

	if (page->inode_t.bank != *bank) {
		*bank = page->inode_t.bank;

		if ((ret = __osPfsRWInode(pfs, inode, PFS_READ, *bank)) != 0) {
			return ret;
		}
	}

	*page = inode->inode_page[page->inode_t.page];

	if (!CHECK_IPAGE(*page, *pfs)) {
		if (page->ipage == 1) {
			return PFS_ERR_INVALID;
		}

		return PFS_ERR_INCONSISTENT;
	}

	return 0;
}

s32 osPfsReadWriteFile(OSPfs* pfs, s32 fileNo, u8 flag, int offset, int size, u8* data)
{
	s32 ret;
	__OSDir dir;
	__OSInode inode;
	__OSInodeUnit curPage;
	s32 curBlock;
	s32 blockSize;
	u8* buffer;
	u8 bank;
	u16 blockno;

	if (fileNo >= pfs->dir_size || fileNo < 0) {
		return PFS_ERR_INVALID;
	}

	if (size <= 0 || (size % BLOCKSIZE) != 0) {
		return PFS_ERR_INVALID;
	}

	if (offset < 0 || (offset % BLOCKSIZE) != 0) {
		return PFS_ERR_INVALID;
	}

	if (!(pfs->status & PFS_INITIALIZED)) {
		return PFS_ERR_INVALID;
	}

	if (__osCheckId(pfs) == PFS_ERR_NEW_PACK) {
		return PFS_ERR_NEW_PACK;
	}

	if (pfs->activebank != 0 && (ret = __osPfsSelectBank(pfs, 0)) != 0) {
		return ret;
	}

	if ((ret = __osContRamRead(pfs->queue, pfs->channel, pfs->dir_table + fileNo, (u8*)&dir)) != 0) {
		return ret;
	}

	if (dir.company_code == 0 || dir.game_code == 0) {
		return PFS_ERR_INVALID;
	}

	if (!CHECK_IPAGE(dir.start_page, *pfs)) {
		if (dir.start_page.ipage == 1) {
			return PFS_ERR_INVALID;
		}

		return PFS_ERR_INCONSISTENT;
	}

	if (flag == PFS_READ && ((dir.status & DIR_STATUS_OCCUPIED) == 0)) {
		return PFS_ERR_BAD_DATA;
	}

	bank = 255;
	curBlock = offset / BLOCKSIZE;
	curPage = dir.start_page;

	while (curBlock >= 8) {
		if ((ret = __osPfsGetNextPage(pfs, &bank, &inode, &curPage)) != 0) {
			return ret;
		}

		curBlock -= 8;
	}

	blockSize = size / BLOCKSIZE;
	buffer = data;

	while (blockSize > 0) {
		if (curBlock == 8) {
			if ((ret = __osPfsGetNextPage(pfs, &bank, &inode, &curPage)) != 0) {
				return ret;
			}

			curBlock = 0;
		}

		if (pfs->activebank != curPage.inode_t.bank && (ret = __osPfsSelectBank(pfs, curPage.inode_t.bank)) != 0) {
			return ret;
		}

		blockno = curPage.inode_t.page * PFS_ONE_PAGE + curBlock;

		if (flag == PFS_READ) {
			ret = __osContRamRead(pfs->queue, pfs->channel, blockno, buffer);
		} else {
			ret = __osContRamWrite(pfs->queue, pfs->channel, blockno, buffer, 0);
		}

		if (ret != 0) {
			return ret;
		}

		buffer += BLOCKSIZE;
		curBlock++;
		blockSize--;
	}

	if (flag == PFS_WRITE && !(dir.status & DIR_STATUS_OCCUPIED)) {
		dir.status |= DIR_STATUS_OCCUPIED;

		if (pfs->activebank != 0 && (ret = __osPfsSelectBank(pfs, 0)) != 0) {
			return ret;
		}

		if ((ret = __osContRamWrite(pfs->queue, pfs->channel, pfs->dir_table + fileNo, (u8*)&dir, 0)) != 0) {
			return ret;
		}
	}

	return __osPfsGetStatus(pfs->queue, pfs->channel);
}
